regproc.c

postgresql8.3.4源码,开源数据库

	Oid			oprid = PG_GETARG_OID(0);
	char	   *result;
	HeapTuple	opertup;

	if (oprid == InvalidOid)
	{
		result = pstrdup("0");
		PG_RETURN_CSTRING(result);
	}

	opertup = SearchSysCache(OPEROID,
							 ObjectIdGetDatum(oprid),
							 0, 0, 0);

	if (HeapTupleIsValid(opertup))
	{
		Form_pg_operator operform = (Form_pg_operator) GETSTRUCT(opertup);
		char	   *oprname = NameStr(operform->oprname);

		/*
		 * In bootstrap mode, skip the fancy namespace stuff and just return
		 * the oper name.  (This path is only needed for debugging output
		 * anyway.)
		 */
		if (IsBootstrapProcessingMode())
			result = pstrdup(oprname);
		else
		{
			FuncCandidateList clist;

			/*
			 * Would this oper be found (uniquely!) by regoperin? If not,
			 * qualify it.
			 */
			clist = OpernameGetCandidates(list_make1(makeString(oprname)),
										  '\0');
			if (clist != NULL && clist->next == NULL &&
				clist->oid == oprid)
				result = pstrdup(oprname);
			else
			{
				const char *nspname;

				nspname = get_namespace_name(operform->oprnamespace);
				nspname = quote_identifier(nspname);
				result = (char *) palloc(strlen(nspname) + strlen(oprname) + 2);
				sprintf(result, "%s.%s", nspname, oprname);
			}
		}

		ReleaseSysCache(opertup);
	}
	else
	{
		/*
		 * If OID doesn't match any pg_operator entry, return it numerically
		 */
		result = (char *) palloc(NAMEDATALEN);
		snprintf(result, NAMEDATALEN, "%u", oprid);
	}

	PG_RETURN_CSTRING(result);
}

/*
 *		regoperrecv			- converts external binary format to regoper
 */
Datum
regoperrecv(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidrecv, so share code */
	return oidrecv(fcinfo);
}

/*
 *		regopersend			- converts regoper to binary format
 */
Datum
regopersend(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidsend, so share code */
	return oidsend(fcinfo);
}


/*
 * regoperatorin		- converts "oprname(args)" to operator OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '0' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_operator entry.
 */
Datum
regoperatorin(PG_FUNCTION_ARGS)
{
	char	   *opr_name_or_oid = PG_GETARG_CSTRING(0);
	Oid			result;
	List	   *names;
	int			nargs;
	Oid			argtypes[FUNC_MAX_ARGS];

	/* '0' ? */
	if (strcmp(opr_name_or_oid, "0") == 0)
		PG_RETURN_OID(InvalidOid);

	/* Numeric OID? */
	if (opr_name_or_oid[0] >= '0' &&
		opr_name_or_oid[0] <= '9' &&
		strspn(opr_name_or_oid, "0123456789") == strlen(opr_name_or_oid))
	{
		result = DatumGetObjectId(DirectFunctionCall1(oidin,
										  CStringGetDatum(opr_name_or_oid)));
		PG_RETURN_OID(result);
	}

	/*
	 * Else it's a name and arguments.  Parse the name and arguments, look up
	 * potential matches in the current namespace search list, and scan to see
	 * which one exactly matches the given argument types.	(There will not be
	 * more than one match.)
	 *
	 * XXX at present, this code will not work in bootstrap mode, hence this
	 * datatype cannot be used for any system column that needs to receive
	 * data during bootstrap.
	 */
	parseNameAndArgTypes(opr_name_or_oid, true, &names, &nargs, argtypes);
	if (nargs == 1)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_PARAMETER),
				 errmsg("missing argument"),
				 errhint("Use NONE to denote the missing argument of a unary operator.")));
	if (nargs != 2)
		ereport(ERROR,
				(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
				 errmsg("too many arguments"),
				 errhint("Provide two argument types for operator.")));

	result = OpernameGetOprid(names, argtypes[0], argtypes[1]);

	if (!OidIsValid(result))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("operator does not exist: %s", opr_name_or_oid)));

	PG_RETURN_OID(result);
}

/*
 * format_operator		- converts operator OID to "opr_name(args)"
 *
 * This exports the useful functionality of regoperatorout for use
 * in other backend modules.  The result is a palloc'd string.
 */
char *
format_operator(Oid operator_oid)
{
	char	   *result;
	HeapTuple	opertup;

	opertup = SearchSysCache(OPEROID,
							 ObjectIdGetDatum(operator_oid),
							 0, 0, 0);

	if (HeapTupleIsValid(opertup))
	{
		Form_pg_operator operform = (Form_pg_operator) GETSTRUCT(opertup);
		char	   *oprname = NameStr(operform->oprname);
		char	   *nspname;
		StringInfoData buf;

		/* XXX no support here for bootstrap mode */

		initStringInfo(&buf);

		/*
		 * Would this oper be found (given the right args) by regoperatorin?
		 * If not, we need to qualify it.
		 */
		if (!OperatorIsVisible(operator_oid))
		{
			nspname = get_namespace_name(operform->oprnamespace);
			appendStringInfo(&buf, "%s.",
							 quote_identifier(nspname));
		}

		appendStringInfo(&buf, "%s(", oprname);

		if (operform->oprleft)
			appendStringInfo(&buf, "%s,",
							 format_type_be(operform->oprleft));
		else
			appendStringInfo(&buf, "NONE,");

		if (operform->oprright)
			appendStringInfo(&buf, "%s)",
							 format_type_be(operform->oprright));
		else
			appendStringInfo(&buf, "NONE)");

		result = buf.data;

		ReleaseSysCache(opertup);
	}
	else
	{
		/*
		 * If OID doesn't match any pg_operator entry, return it numerically
		 */
		result = (char *) palloc(NAMEDATALEN);
		snprintf(result, NAMEDATALEN, "%u", operator_oid);
	}

	return result;
}

/*
 * regoperatorout		- converts operator OID to "opr_name(args)"
 */
Datum
regoperatorout(PG_FUNCTION_ARGS)
{
	Oid			oprid = PG_GETARG_OID(0);
	char	   *result;

	if (oprid == InvalidOid)
		result = pstrdup("0");
	else
		result = format_operator(oprid);

	PG_RETURN_CSTRING(result);
}

/*
 *		regoperatorrecv			- converts external binary format to regoperator
 */
Datum
regoperatorrecv(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidrecv, so share code */
	return oidrecv(fcinfo);
}

/*
 *		regoperatorsend			- converts regoperator to binary format
 */
Datum
regoperatorsend(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidsend, so share code */
	return oidsend(fcinfo);
}


/*
 * regclassin		- converts "classname" to class OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_class entry.
 */
Datum
regclassin(PG_FUNCTION_ARGS)
{
	char	   *class_name_or_oid = PG_GETARG_CSTRING(0);
	Oid			result = InvalidOid;
	List	   *names;

	/* '-' ? */
	if (strcmp(class_name_or_oid, "-") == 0)
		PG_RETURN_OID(InvalidOid);

	/* Numeric OID? */
	if (class_name_or_oid[0] >= '0' &&
		class_name_or_oid[0] <= '9' &&
		strspn(class_name_or_oid, "0123456789") == strlen(class_name_or_oid))
	{
		result = DatumGetObjectId(DirectFunctionCall1(oidin,
										CStringGetDatum(class_name_or_oid)));
		PG_RETURN_OID(result);
	}

	/* Else it's a name, possibly schema-qualified */

	/*
	 * In bootstrap mode we assume the given name is not schema-qualified, and
	 * just search pg_class for a match.  This is needed for initializing
	 * other system catalogs (pg_namespace may not exist yet, and certainly
	 * there are no schemas other than pg_catalog).
	 */
	if (IsBootstrapProcessingMode())
	{
		Relation	hdesc;
		ScanKeyData skey[1];
		SysScanDesc sysscan;
		HeapTuple	tuple;

		ScanKeyInit(&skey[0],
					Anum_pg_class_relname,
					BTEqualStrategyNumber, F_NAMEEQ,
					CStringGetDatum(class_name_or_oid));

		hdesc = heap_open(RelationRelationId, AccessShareLock);
		sysscan = systable_beginscan(hdesc, ClassNameNspIndexId, true,
									 SnapshotNow, 1, skey);

		if (HeapTupleIsValid(tuple = systable_getnext(sysscan)))
			result = HeapTupleGetOid(tuple);
		else
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_TABLE),
			   errmsg("relation \"%s\" does not exist", class_name_or_oid)));

		/* We assume there can be only one match */

		systable_endscan(sysscan);
		heap_close(hdesc, AccessShareLock);

		PG_RETURN_OID(result);
	}

	/*
	 * Normal case: parse the name into components and see if it matches any
	 * pg_class entries in the current search path.
	 */
	names = stringToQualifiedNameList(class_name_or_oid);

	result = RangeVarGetRelid(makeRangeVarFromNameList(names), false);

	PG_RETURN_OID(result);
}

/*
 * regclassout		- converts class OID to "class_name"
 */
Datum
regclassout(PG_FUNCTION_ARGS)
{
	Oid			classid = PG_GETARG_OID(0);
	char	   *result;
	HeapTuple	classtup;

	if (classid == InvalidOid)
	{
		result = pstrdup("-");
		PG_RETURN_CSTRING(result);
	}

	classtup = SearchSysCache(RELOID,
							  ObjectIdGetDatum(classid),
							  0, 0, 0);

	if (HeapTupleIsValid(classtup))
	{
		Form_pg_class classform = (Form_pg_class) GETSTRUCT(classtup);
		char	   *classname = NameStr(classform->relname);

		/*
		 * In bootstrap mode, skip the fancy namespace stuff and just return
		 * the class name.	(This path is only needed for debugging output
		 * anyway.)
		 */
		if (IsBootstrapProcessingMode())
			result = pstrdup(classname);
		else
		{
			char	   *nspname;

			/*
			 * Would this class be found by regclassin? If not, qualify it.
			 */
			if (RelationIsVisible(classid))
				nspname = NULL;
			else
				nspname = get_namespace_name(classform->relnamespace);

			result = quote_qualified_identifier(nspname, classname);
		}

		ReleaseSysCache(classtup);
	}
	else
	{
		/* If OID doesn't match any pg_class entry, return it numerically */
		result = (char *) palloc(NAMEDATALEN);
		snprintf(result, NAMEDATALEN, "%u", classid);
	}

	PG_RETURN_CSTRING(result);
}

/*
 *		regclassrecv			- converts external binary format to regclass
 */
Datum
regclassrecv(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidrecv, so share code */
	return oidrecv(fcinfo);
}

/*
 *		regclasssend			- converts regclass to binary format
 */
Datum
regclasssend(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidsend, so share code */
	return oidsend(fcinfo);
}


/*
 * regtypein		- converts "typename" to type OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_type entry.
 *
 * In bootstrap mode the name must just equal some existing name in pg_type.
 * In normal mode the type name can be specified using the full type syntax
 * recognized by the parser; for example, DOUBLE PRECISION and INTEGER[] will
 * work and be translated to the correct type names.  (We ignore any typmod
 * info generated by the parser, however.)
 */
Datum
regtypein(PG_FUNCTION_ARGS)
{
	char	   *typ_name_or_oid = PG_GETARG_CSTRING(0);
	Oid			result = InvalidOid;
	int32		typmod;

	/* '-' ? */
	if (strcmp(typ_name_or_oid, "-") == 0)
		PG_RETURN_OID(InvalidOid);

	/* Numeric OID? */
	if (typ_name_or_oid[0] >= '0' &&
		typ_name_or_oid[0] <= '9' &&
		strspn(typ_name_or_oid, "0123456789") == strlen(typ_name_or_oid))
	{
		result = DatumGetObjectId(DirectFunctionCall1(oidin,
										  CStringGetDatum(typ_name_or_oid)));
		PG_RETURN_OID(result);
	}

	/* Else it's a type name, possibly schema-qualified or decorated */

	/*
	 * In bootstrap mode we assume the given name is not schema-qualified, and
	 * just search pg_type for a match.  This is needed for initializing other
	 * system catalogs (pg_namespace may not exist yet, and certainly there
	 * are no schemas other than pg_catalog).
	 */
	if (IsBootstrapProcessingMode())
	{
		Relation	hdesc;
		ScanKeyData skey[1];
		SysScanDesc sysscan;
		HeapTuple	tuple;

		ScanKeyInit(&skey[0],
					Anum_pg_type_typname,
					BTEqualStrategyNumber, F_NAMEEQ,
					CStringGetDatum(typ_name_or_oid));

		hdesc = heap_open(TypeRelationId, AccessShareLock);
		sysscan = systable_beginscan(hdesc, TypeNameNspIndexId, true,
									 SnapshotNow, 1, skey);

		if (HeapTupleIsValid(tuple = systable_getnext(sysscan)))
			result = HeapTupleGetOid(tuple);
		else
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_OBJECT),
					 errmsg("type \"%s\" does not exist", typ_name_or_oid)));

		/* We assume there can be only one match */

		systable_endscan(sysscan);
		heap_close(hdesc, AccessShareLock);

		PG_RETURN_OID(result);
	}

	/*
	 * Normal case: invoke the full parser to deal with special cases such as
	 * array syntax.
	 */
	parseTypeString(typ_name_or_oid, &result, &typmod);

	PG_RETURN_OID(result);
}

/*
 * regtypeout		- converts type OID to "typ_name"
 */
Datum
regtypeout(PG_FUNCTION_ARGS)
{